As a mechanical element for guiding linear or curvilinear of an object such as a table, there is known a motion guide device having rolling elements such as balls or rollers in a guide part. As agile motion is obtained, the motion guide device is utilized in various fields including robots, machining tools, semiconductor/liquid crystal manufacturing devices, medical machines and the like.
One of such motion guide devices is a linear guide having a raceway rail mounted on a base and a moving block mounted on the raceway rail to be movable relative to the raceway rail. In the raceway rail, a rolling-element rolling part is formed extending in the longitudinal direction. In the moving block, a loaded rolling-element rolling groove is formed facing the rolling-element rolling part and a rolling-element circulation passage is provided for circulating rolling elements. Between the rolling-element rolling part of the raceway rail and the loaded rolling-element rolling part of the moving block, rolling elements are arranged. When the moving block moves linearly relative to the raceway rail, the rolling elements roll between the raceway rail and the moving block.
In these days, weight reduction is also desired for motion guide devices as mechanical elements. Particularly, weight reduction is desired for customer motion guide devices on which heavy load is not applied, motion guide devices which are built in multi-joint robots, motion guide devices which are built in XY tables and the like.
As a technique for weight reduction of a moving block of a motion guide device, the patent document 1 discloses a moving block having a core 21 where rolling-element rolling parts 21a are formed and a molded body 22 made of resin or aluminum around the core 21, the core 21 being inserted into a die and the molded body 22 being formed integral with the core 21, as illustrated in FIG. 23.
The patent document 2 discloses a moving block having a hollow block 31 in which rolling-element rolling parts 31a are formed, the hollow block 31 being filled with a filling material 32 of resin or aluminum, which is illustrated in FIG. 24.
The patent document 3 discloses a moving block having a rolling plate made of stainless-steel where rolling-element rolling parts 41a are formed, a mounting plate 42 made of stainless-steel for mounting the moving block onto a counterpart device and a molded body 43 made of resin integrally formed with these plates 41 and 42.    [Patent Document 1] Japanese Patent No. 3550208    [Patent Document 2] Japanese Patent Application Laid-open No. 8-326747    [Patent Document 3] Japanese Patent Publication No. 7-18448